1. Field of the Invention
The present invention relates to an image projector and, more particularly, to a projection system having multiple image display screens in a plurality of directions installed outdoors, e.g., on the roof of a building, to display information such as news or advertisements for public viewers.
2. Description of the Related Art
A projector, such as a video projector or a projection TV, forms an image using an image forming means such as a small cathode ray tube (CRT) or liquid crystal display (LCD) and projects the image by magnifying the same onto a large screen via a projection lens. Such projection systems are largely divided into two types, a front-type projector and a rear-type projection system according to the method of projecting the images, i.e., whether the image is projected to the fore side or the back side of the screen.
In the front-type projector, an image is projected to the screen from an image source installed at the front of the screen, whereas the image is projected to the back side of the screen from the image source installed to the rear of the screen in the rear-type projection system.
As shown in FIG. 1, a display apparatus 100 is installed on the roof of a building 10 for displaying advertisements or news to the public. The image is displayed on a large screen 101 using a CRT of red (R), green (G), and blue (B) colors or a multitude of light emitting diodes (LEDs) arranged in a matrix forming pixels.
The conventional display apparatus for outdoor advertisements requires high installation costs in forming a large screen and displays only in one direction which limits viewing from different directions.